Photographic physical developers comprising a water soluble salt of an alkenyl amine compound as an ionic surfactant and processes utilizing this developer

ABSTRACT

In a stabilized photographic physical developer comprising a solution of silver ions reducible to silver metal, a reducing agent for reducing said silver ions to silver metal, and an ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound. A preferred physical developer additionally comprises a second different ionic surfactant which is preferably a water soluble salt of a primary alkyl amine compound. The salt of the alkenyl amine compound is preferably present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer without the alkenyl amine compound. Photographic physical development processes comprise contacting a copy medium comprising a catalytic nuclei image which catalyzes deposition of metal from a physical developer, with the abovementioned improved physical developer. Preferred processes relate to forming printing plates or film transparencies.

United States Patent 1191 Eckert 'et a1.

Assignee: Itek Corporation, Lexington, Mass.

Filed: Dec. 26, 1972 App]. No.: 318,443

us. c1 96/48 PD, 96/664, 96/33, p 106/1, 117/1301; 1111. C1 G036 5/24 Field 61 Search 96/664, 66.5, 48 PD, 33;

References Cited UNITED STATES PATENTS 1 H1964 Jonker et a1. 96/664 l/l967 Horvath et al. 117/130 E [4 1 Apr. 30, 1974 Primary Examirier-Rnttldl-I. Smith Assistant ExaminerWon H Louie, Jr.

' Attbmeyfilgent, airmqiome'r GEE Hebert L.

Nathans; W. Gary Goodson In a stabilized photographic physical developer comprising a solution of silver ions reducible to silver metal, a reducing agent for reducing said silver ions to silver metal, and an ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound. A preferred physical developer additionally comprises a second different ionic surfactant which is preferably a water soluble salt of a primary alkyl amine compound. The salt of the alkenyl amine compound is preferably present in an amount sufficient to increase the life of the developer at least SO percent when compared to the life of an identical developer without the alkenyl amine compound. Photographic physical development processes comprise contacting a copy medium comprising a catalytic nuclei image which catalyzes deposition of metal from a physical developer, with the abovementioned improved physical developer. Preferred processes relate to forming printing plates or film transparencies.

39 Claims, N0 Drawings PIIOTOGRAPHIC PHYSICAL DEVELOPERS COMPRISING A WATER SOLUBLE SALT OF AN ALKENYL AMINE COMPOUND AS AN IONIC SURFACTANT AND PROCESSES UTILIZING THIS DEVELOPER CROSS REFERENCES TO RELATED APPLICATIONS This application is related to copending applications U.S. Ser. No. 54,627 filed July 13, 1970, 55,238 filed July 13, 1970, and 174,102 filed Aug. 23, 1971, all in the names of Gracia et al. and to a U.S. patent application Ser. No. 258,769 filed June 1, 1972 entitled Processes Utilizing Photographic Element Containing a Physical Development Activator in the name of H. Lerner. These applications are hereby incorporated by reference.

BACKGROUND OF THE INVENTION This invention relates to the field of photographic physical developers, and processes using these developers.

Processes utilizing photographic physical developers" comprising a solution of metal ions and a reducing agent for these metal ions have been around for many years. In these processes an image pattern of physical development nuclei is formed such as by exposure of a photographic element comprising a photosensitive layer which upon exposure generates physical development nuclei. The photographic element containing the image pattern of physical development nuclei is then contacted with'a physical developer to produce a metallic image in those areas where the physical development nuclei catalyze the selective deposition of metal.

Two types of physical development processes have achieved commercial success. The first is the diffusion transfer type of physical development which may more accurately be termed solution physical development wherein a solvent is added to the developer to thereby dissolve the silver halide in the unexposed portions of a silver halide copy medium thereby allowing the silver ions to be utilized for image formation on suitable physical development nuclei. These nuclei may be either in a separate layer on the same sheet as the silver halide layer or on a separate transfer sheet as is well known in the Polaroid process. A second physical development process which has achieved some commercial success is one wherein the metal ion solution is applied in a separate bath to the exposed photographic element and subsequently a reducing agent bath is applied to the element.

However, at the present time applicants are unaware of any commercial photographic processes utilizing a unitary physical developer comprising a solution of metal ions and a photographic reducing agent for these metal ions. A significant reason for this lack of commercial success with the unitary physical developer has been the lack of stability of this physical developer solution. A number of attempts have been made to overcome the instability of these physical developers by the addition of ionic surfactants, antifogging agents, and the like. See for example, U.S. Pat. Nos. 3,157,502 and 3,390,998, incorporated herein by reference. See also Jonker et al. in Photographic Science and Engineering, vol. 13, 1969, pp. 38-44, also incorporated herein by reference, wherein a preferred unitary physical developer known as a stabilized photographic physical developer is discussed comprising a solution of ferrous ions, ferric ions, silver ions, a complexing agent such as citric acid, and an ionic surfactant as a stabilizing agent for the physical developer. Preferably the developer also comprises a non-ionic surfactant for solubilizing the ionic surfactant of the developer. By adjusting the concentrations of the various components of this physical developer, relatively rapid rates of development have been achieved while maintaining a relatively stable physical developer. However, even with this preferred physical developer while the stability of the solution may be good for several days when not in use, while in continual use this developer depending upon the concentration and activity, deteriorates within the matter of hours or at the best a few days. This lack of stability in actual use has been an especially serious problem when attempting to utilize automatic processing equipment since even utilizing a replenishment system the developer must be replaced completely at very frequent intervals because of serious degradation problems. This causes serious economic problems due to the increased developer cost; the labor involved in changing the developer and cleaning processing equipment; and the lost production caused by the shut-down time.

H. Lerners invention in U.S. Ser. No. 258,769 attempts to overcome these problems of the prior art by utilizing a unitary physical developer of lower activity or development rate than was believed possible in the prior art. Such a developer is, of course, inherently more stable than a developer of greater activity.

The low activity or low AE developer can be utilized since a physical development activator material such as an organic acid which complexes the ferric ion of the developer is present in the copy medium so that the physical developer is actually acitvated locally at the site where development takes place in the copy medium. A preferred physical development activator material is a complexing agent for the ferric ion of the physical developer.

However, it is often desirable in processes such as those relating to producing printing plates to have a relatively high activity developer in order to get the large quantities of metal deposited, e.g., 1-14 grams per square meter, as rapidly as possible. Therefore, it would be desirable to obtain stabilized physical developers having a greater inherent stability regardless of whether they are low activity developers or high activity developers. It is therefore an object of this invention to produce photographic stabilized physical developers having inherently improved stability and especially ones which are suitable for producing metal imaged printing plates. Additionally, it is an object to produce physical developers having an inherent stability such that a great deal of latitude exists in varying the activity of the developer and other photographic properties of the final print such as gamma and cleanliness of the background areas. It is also an object of this invention to produce photographic film transparencies by this developer having improved stability. It is also an object to produce a developer having improved stability in actual use and especially one that can be utilized in automatic processing equipment with a developer replenishment system to obtain uniform development over prolonged time periods such as several days.

BRIEF SUMMARY OF THE INVENTION In a photographic physical developer preferably having an acidic pH and comprising an aqueous solution of a water soluble silver salt reducible to silver metal, a photographic ferrous/ferric reducing agent for reduc-' ing the salt to metal, at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound preferably having at least eight carbon atoms in the alkenyl group. A preferred physical developer is one which contains an additional different ionic surfactant which is preferably a primary alkyl amine compound having an alkyl group attached to the nitrogen atom and having at least eight carbon atoms in the alkyl group. A preferred physical deloper is one wherein the reducing agent system is a solution of ferrous ions and ferric ions. Preferably also the reducing agent system for reducing the silver ions to silver metal contains a complexing organic acid for complexing the ferric ions. A non-ionic surfactant is preferably also present in the developer. Improved physical development processes comprise contacting a copy medium comprising a catalytic nuclei image which selectively catalyzes deposition of silver metal from a physical developer, when contacted with the previously mentioned improved physical developers. In preferred processes printing plates and photographic transparencies are produced.

DETAILED DESCRIPTION OF THIS INVENTION The salt of an alkenyl amine of this invention is one which will dissolve in the aqueous physical developer described herein. Thus the salt is preferably water soluble and is preferably the reaction product of an alkenyl amine and an organic acid such as acetic acid. Thus a preferred salt is oleylaminoacetate. The alkenyl amine compound of this invention is an amine containmg The least one alkenyl group having at least eight carbon atoms in the hydrocarbon chain of such group. The term alkenyl group is intended to include hydrocarbon chains containing one or more carbon double bonds, i.e.,

Alkenyl amine compounds suitable for this invention are preferably straight carbon chain amines such as oleyl amine, pamitoleyl amine, and myristoleyl amine.

The salt of an alkenyl amine is preferably present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer without the alkenyl amine compound. When the AE of the developer is more than about 100, it is preferredthat the amine is present in an amount sufficient to increase the life of the developer at least times the life of an identical developer without the alkenyl amine compound.

Preferably, the stabilized physical developers of this invention contain an additional ionic surfactant than the water soluble salt of an alkenyl amine. Using this preferred physical developer, higher gammas and cleaner, fog-free background in the final imaged medium have been obtained, especially when producing printing plates. Also improved freedom from plating on the developer container in use is noted. The preferred additional surfactants are those saturated ionic surfactants disclosed in US. Pat. No. 3,157,502. A preferred class of these surfactants is the primary alkyl amines having an alkyl group attached to the nitrogen atom and having at least eight carbon atoms in the alkyl group. Particularly preferred is the water soluble salt of a primary alkyl amine known by the tradename Armac 12D which is a combination of percent by weight of C H NH 'CH COOI-I and of 9 percent by weight of C14H29NH2'CH3COOH.

Additionally, a material which helps to increase the solubility of the ionic surfactant in the physical developer is preferably added to the physical developer of this invention. A non-ionic surfactant is an example of such a material. A preferred class of non-ionic surfactants is the ethylene oxide condensates of an aliphatic alcohol such as those known under the tradenames Lissapol N or Synthropol N.

The activity of the developer or AE may be varied by techniques known to the art such as varying the relative proportions of ferrous ion to ferric ion and the like. Ordinarily a AE of at least about is preferred. However, a AE of between about 100 and 400 is preferred for most photographic purposes. However, when utilizing a physical development activator material in the photographic copy medium, it is often desirable to utilize physical developers having a AE of less than 100. Utilizing a physical development activator material in the photographic copy medium, a AE of between about 60 and 100 is especially preferred for producing printing plates.

In the physical developers employed, the reducible metal ion is usually silver although a person of average skill in the art will readily recognize that mercury ions and the like which are readily reduced by the ferrous/ferric reducing system of this invention will work equally well.

A particularly effective unitary physical developer is composed of silver ions; as the reducing agent system therefor, ferrous ions and ferric ions; and preferably a material which preferentailly forms a complex with the ferric ions of the developer such as an organic acid. The ferrous ions are of course the specific reducing agent. However, the ratio of ferrous ions to ferric ions helps determine the activity or AE of the developer.

Suitable organic acids for use in the developer and as a physical development activator for incorporating with the photosensitive layer are dicarboxylic acids such as oxalic, malic, maleic, malonic, or succinic acids and hydroxy carboxylic acids such as salicylic, tartaric, lactic, mandelic, glycolic, and citric acids. Especially preferred are the hydroxy carboxylic acids. Preferred as physical development activator materials for incorporating with the photosensitive layer are the soluble salts of these acids such as the alkali and alkaline earth metal, and ammonium salts of these acids. The ammonium salts of citric acid, tartaric acid, and lactic acid are especially preferred due to their especially good results. Other complexing agents suitable as physical development activator materials are complexing agents such as amino acids such as glycine, amines such as ethylenediamine, and B-diketones such as acetylacetone.

A combination of malic and malonic acids have been found preferable for use in the physical developer of this invention for use in an automatic processor for high speed development (about 100 feet per minute) of photographic film because of the especially desirable black image tones achieved. Also the physical developer containingthese acids when used in such an automatic processer appears to have improved stability and to be less readily'oxidized by the oxygen of the air than when containing other organic acids. Citric acid is the preferred organic acid for use in the physical developer of this invention when the developer is used to produce printing plates because of the exceptionally high gamma produced.

The physical developer of this invention is preferably one having an acidic pH. Preferably the pH is less than about 6 and most preferably less than about 3.

The catalytic or physical development nuclei of this invention is preferably a metal such as silver, gold, mercury, platinum, palladium, metal sulfides such as silver sulfide, graphite, or the like. In a silver halide copy medium, the latent silver image forms in the silver halide grain in the emulsion upon exposure and physical development is used to render the latent image visible. When a photosensitive material such as a metal oxide such as titanium dioxide, zinc oxide, or tin oxide are exposed and contacted with a solution of a reducible metal ion, a latent metal image is formed, visible or invisible, which can then be amplified by means of a unitary physical developer or it is possible to go directly into the unitary physical developer without first going into a metal ion bath.

The image of catalytic nuclei can be 1. the image formed on photoexposure, e.g., the latent silver image in silver halide emulsions or the reversible latent image on a reversibly activatable photoconductor such as titanium dioxide;

2. the irreversible image formed by contacting an exposed photoconductor-bearing medium with a sensitizing metal ion, e.g., a solution of silver ion, which can lead to an invisible irreversible image or a visible metal image;

3. the latent ferrous ion image formed by photoexposure of a ferric salt-sensitized medium and then sensitized with silver ion solution to form a silver image;

4. a conductive image or germ nuclei image produced byprinting orby writing as taught in commonly owned copending US. Ser. No. 2,440, filed Jan. 12, 1970, now abandoned;

5. by physically placing a metallic image adjacent to the support;

6. by diffusion transfer of metal ions as taught in US.

Pat. No. 3,300,306, by means of an imagewise exposed photopolymer layer over a germ nuclei layer as for example in commonly owned copending application Ser. No. 697,948, filed Jan. 15, 1968 now U.S. Pat. No. 3,615,446;

7. the germ nuclei image formed by exposure of a prefogged photosensitive material such as lead iodide or AS253 such as taught in Malinowski, Photographic Science and Engineering, Vol. 15, No. 3, May-June, incorporated herein by reference; or

8. the conventionally developed (primarily chemical. development) image of a silver halide emulsion.

A preferred photosensitive material comprises a photoconductor such as silver halide or a photoconductor which becomes reversibly activated upon exposure to activating radiation and is capable of causing chemical reaction in the exposed areas. The photoconductor is preferably of a particulate nature, preferably incorporated in a water permeable binder, and deposited as a very thin, removable layer upon the support, especially on a superficially roughened support, in such a way that the photoconductor is impregnated at least in part within the roughened portion of the support. This is readily accomplished for example by depositing a photoconductor, such as silver chloride, in a solvent-binder solution of relatively low viscosity and then coating this composition onto the roughened support. The coating composition may be allowed to dry. Such a support which has a photoconductor-binder coating will preferably have a very thin coating which is solvent permeable and will thereby allow rapid processing in the preferred developer systems.

lt is also understood that a catalytic nuclei image can be produced by applying physical development or germ nuclei to the metallic support. This can be done by inscribing on the metallic support with, for example, a graphite pencil or may be done by applying a germ nuclei layer preferably in a binder and coated with a photo-impermeablizable layer, then exposing to impermeablize the layer in exposed areas. Germ nuclei can be any material which will catalyze deposition of metal from the physical developer. Many such materials are known to the art, such as metal sulfide, finely divided metal particles, graphite and the like.

The preferred photosensitive media are those comprising silver halide as the photosensitive material. Such photosensitive media are more than adequately described in the literature and are well known to those in the art. Especially preferred silver halide media are those which contain a low content of silver halide in the photosensitive layer and especially those which have a stoichiometric excess of halide ion based upon the amount of silver ion present in the photosensitive layer.

The so-called low silver content, thin photosensitive layer constitute a preferred form of the invention, particularly with metal substrates for the production of printing plates, electrical components, and the like. The silver halide employed is that which is conventionally used in photography and is made in the conventional way, i.e., by reaction in aqueous systems of soluble silver salt such as silver nitrate or sulfate and a soluble alkali metal halide, such as sodium chloride, sodium bromide or sodium iodide, or corresponding potassium salts. The formation of the particles of silver halide can be controlled to permit any desired particle size, ranging as little as 30 to 50 Angstrom units up to conventional particle size. Preferred methods are those which encourage fine particle size usually less than 0.5 micron. For general convenience, such fine particle size ing or after exposure. For example, physical development activator materials as described above, sensitizing dyes, thiourea, toners, mercuric salts or the like can be added for their known photographic effects, e.g., thiourea to assist in formation of black photographic images, and the sensitizing dyes to alter the spectral response of the photosensitive layer on photoexposure.

The photosensitive material can also be any of the literature, for example, U.S. Pat. Nos. 3,380,823, or 3,623,865, incorporated herein by reference. Generally the preferred photoconductors are silver halide or compounds of a metal with a nonmetallic element of Periodic Group VI. Preferably, these photoconductors are metal oxides or sulfides, such as titanium dioxide, zinc oxide, zinc sulfide, cadmium sulfide, and cerium oxide, among others.:.Preferred oxides are titanium dioxide, zinc oxide, tin oxide and mixtures thereof.

The physical development nuclei or photosensitive material and the physical developer activator material in the selected binder are applied to the substrate using any of the art-recognized techniques, as by use of rollers, in the desired thickness. After drying the photographic media are ready for use. lf desired a top coating can be applied to protect the photographic emulsion. Of course, the emulsion can also contain substances commonly employed with the specific photosensitive material, such as dye-sensitizers, sensitizing-metal salts, such as silver and copper salts, photographic reducing agents, and such materials commonly used in photographic emulsions.

The photoexposure step employed is the same as normally used for the selected photosensitive material. The photo-processing of the exposed medium is also the same as normally employed.

The substrate for the present media include all of the substrates commonly employed such as paper, plastics and metal substrates. For example, cellulose acetate and polyethylene terephthalate can be used for transparent films while metals, such as aluminum and iron, as well as alloys thereof, can be used and are particularly adapted for photographically producing printing plates and printed electrical components, e.g., printed electrical circuits, capacitors, and the like, as well as nameplates and decorative metal plates. The preferred support for making long run printed slates are those on grained metal supports. Anodized aluminum supports give especially desirable results.

For the preferred metallic supports, any suitable metallic or substantially metallic backing of sufficient strength and durability to satisfactorily serve as a reproduction carrier can be employed. The support may be in any form such as, for example, sheets, ribbons, rolls, etc. This sheet may be made of any suitable metal or their alloys, as for example the hydrophilic metals such as chromium, nickel, lead, stainless steel, magnesium, or aluminum; or the oleophilic metals such as copper or zinc. Aluminum is preferred because of its desirable physical and chemical properties, as well as its economy. Aluminum as used herein is intended to include alloys of aluminum such as aluminum containing minor amounts of manganese, copper or magnesium. A porous anodized surface is especially preferred for the aluminum support. The anodized surface may be sealed by heating. However, the unsealed surface is preferred because of the improved adhesion that can be obtained between the metal image and the aluminum support. For long run printing plates an alloy such as Type 1100 aluminum is used which will resist cracking and will have the strength of these long runs.

The preferred metallic support may be of any suitable thickness. However, a thickness from about .006 to .025 inch is preferred for use as printing plates, and preferably for long run printing plates, the thickness is from about 0.012 to 0.015 inch.

The support and imaging metal may be chosen so as to give a good oleophilic-hydrophilic differentiation for use in a lithographic process. Also, by special treatments or the right substrate or imaging metal this process can be used to produce a plate useful in the socalled driographic manner described in US. Pat. No. 3,511,178, incorporated herein by reference.

Grained metallic supports are especially preferred for this invention. This support is capable of forming a bond with a metallic image formed by physical development thus forming a plate capable of being used as a printing plate and preferably as a long run printing plate and which upon testing with the Optical Surface Roughness Meter (OSRM), described below, produces a trace having a peak Height A between about 0.25 and about 0.90 at a Position B of between about 0.35 and about 0.80 and having a psi Value C of between about 0.40 and about 1.0. Such grains may be produced by physically graining, e.g., brush graining, ball graining or sand blasting or by chemical graining, e.g., acid or alkali etching. Chemical graining can be accomplished, for example, suitably by electrochemical treatment in an acid bath such as hydrochloric acid, nitric acid, or a combination of nitric acid and acetic acid.

In a preferred embodiment a long run metallic based printing plates having run lengths comparable to the bimetallic plates are produced (run lengths in excess of 150,000 on a conventional lithographic press under ordinary conditions). For producing line copy, these plates are ones wherein the grain of the metallic, preferably aluminum, support as tested on the OSRM produces a trace having a peak Height A between about 0.50 and about 0.85 at a peak Position B of between about 0.60 and about 0.75 and having a psi Value C between about 0.65 and about 0.90. For producing halftones the trace produced has a peak Height A between about 0.75 and about 0.85 at a peak Position B of between about 0.70 and about 0.75 and having a psi Value C of between about 0.75 and about 0.90.

A long run printing plate as defined herein is an imaged printing plate which when placed upon a conventional lithographic offset high speed web press run under ordinary conditions such as a Harris Cottrell M- 1000 at Colonial Press, lnc., Clinton, Massachusetts, which is a 24% X 36% inches, 4 unit perfecting heat set web offset press running at about 26,000 impressions per hour, on 50 lb. white offset stock using lPl black ink, Dayco non-compressible blankets and Imperial fountain solution, will be capable of producing at least about 100,000 prints of good quality and preferably at least about 150,000 without any substantial loss of quality due to wear of the image or removal of the image from the printing plate.

When an imaged plate performs as a printing plate according to this invention, it is one which will produce at least about 5,000 prints on a conventional, lithographic offset press under ordinary conditions. Typical of such a press is the Harris-Aurelia press.

To measure the grain of the metallic supports utilized in this invention an Optical Surface Roughness Meter (OSRM) is used such as described in commonly owned copending application U.S. Ser. No. 168,938 filed Aug. 4, 1971, in the names of Peter Nisenson and Elliot Blackman, entitled Optical Device for Characterizing the Surface or Other Properties of a Sample, incorporated herein by reference.

The OSRM is useful for characterizing the surface topography of an opaque sample and for characterizing other properties of transparent samples. In the reflecting mode, a laser is useful to illuminate the surface of a rotating sample. Reflected laser light is focused at a pinhole aperture where its intensity is detected. Useful plots of the power spectrum of the reflected coherent light as a function of frequency are obtained which characterize the surface topography of the sample.

For characterizing surface topography of a reflecting surface, the OSRM uses a coherent light source, such as a laser, which provides a beam which is directed through a spatial filter, collimating objective and beam splitter onto the samples surface. The sample is mounted on a rotating support. Surface irregularities modulate the reflected coherent beam which is passed back through thebeam splitter and directed through a transforming objective to focus it at a pinhole aperture which has a phototube positioned behind it. The pinhole aperture is located in the back focal plane of the reflected light. Useful plots of the power spectrum of the reflected coherent light are obtained which characterize the surface topography of the sample.

Since the OSRM measures the coherent power spectra of diffracted light, it is also an advantage that known relationships have been established and are available between coherent power spectra and rough surface statistics. For example, see The Scattering of Electromagnetic Waves from Rough Surfaces by Peter Beckmann and Andre Spizzichino, Pergamon Press, London, 1963. A most important advantage is the exact categorization of surface topographies that can be obtained relatively easily using devices as described herein. For

example, the symmetry or directionality of the statistics of the surface topography can be easily determined with the new devices. This was impossible or at least very difficult with many of the prior art devices.

A most unique and important feature of the OSRM is that it produces a direct display of usable information. It is not necessary to manipulate the data obtained to have meaningful comparisons. In a preferred method of operation, plots can be directly obtained allowing an operator to display the surfaces power spectra and such plots can be used for direct sample to sample comparisons. This is particularly important in quality control applications where the emphasis is often on testing samples quickly.

As described in the copending application, the OSRM generates four traces to characterize the grain of the metallic support. The curves are more simply characterized'using the following four parameters:

a. Peak Height A (vertical axis on a scale of zero to 1.0) of the highest of the four directional traces made on each surface,

b. Peak Position B (horizontal axis on a scale of zero to 1.0) of the highest of these four directional traces made on each surface,

c. Psi Value C which is used as a measure of the amount of fine structure in the surface, and is defined in the following way:

1. The peak Height A and the peak Position B is determined,

2. The height of the OSRM trace for the highest of the four curves is determined at the 0.90 position on the horizontal axis, and

3. the psi Value C is the ratio of the value obtained in (2) and the peak Height A, and

d. The asymmetry--asymmetrical nature is numerically indicated as the value of the difference between peak Height A and the height of the lowest curve at position B on the horizontal axis.

The thickness of the layer of the catalytic nuclei or photosensitive material capable of generating such nuclei, the insulating layer or subbing layer, where present, will depend upon the nature of the photosensitive material, the nature of the binder, where present, the amount of activating radiation utilized and other like factors. However, in order to obtain an imaging medium capable of rapid processing it is preferred that the layer of physical development nuclei or photosensitive material be relatively thin, preferably less than about 2 microns and more preferably less than about 1 micron in thickness. Most preferably, the layer thickness is from about 0.01 to about 0.5 microns, or so thin that it is unlikely that a completely coherent coating exists. However, the thickness of these layers may vary. For example, in the metal support embodiment the photosensitive coating or coating of physical development nuclei may be scraped off except for the portions which are immersed in the roughened surface. This coating thickness may be varied according to the effects desired. However, most preferable is a substrate wherein this coating is less than 1 micron in thickness in order to obtain coherent metal images which are adherently bonded to the support by the rapid processing which is most desired.

In one preferred embodiment an internal diffusion transfer plate is prepared by coating a layer of physical development nuclei such as Carey Lee Silver on a support to a dry thickness of less than about 2 microns in thickness. This layer is in turn coated with a layer of silver halide capable of being exposed and developed in a manner such as disclosed in US. Pat. No. 3,615,437, incorporated herein by reference, except that the physical developer activator material of this invention is incorporated in the plate. Preferably, the image produced by solution physical development is then amplified by means of the stabilized unitary physical developer of this invention instead of the electroplating baths of US. Pat. No. 3,615,437.

When used, the amount of binder to amount of catalytic nuclei or photosensitive material may vary over wide ranges. Preferably, from about weight ratios of nuclei or photosensitive material to binder of 1 to 6 through 6 to l and more preferably from 1 to 1 through 1 to 3.

Irradiation sources which are useful in this invention for producing the intial latent image include any of the usual irradiation means commonly used with the selected photosensitive material. Thus actinic light, X- rays, or gamma rays are effective when photoconductors are used. Beams of electrons and other like particles may also be used in the place of the ordinary forms of electromagnetic radiation for forming an image. These various activating means are designated by the term activating radiation.

Trade or Common Name Formula (Alamine ll) Oleyl amine or octadec-9-ene-l -amine velopment initiator. A preferredcompound is a thiu- (Armac 2D or Mamine 4) 90% CHHHNHCHICOOH ram such as tetramethylthluramdisulfide. This physlcal Dodecylamine development initiator acts to improve the quality of the and metal deposit formed when physical developing an ex- Temdecylam'ne 9% C"H"NH1'CHCOOH posed silver halide plate. (Lissapol N or Additionally, in a preferred embodiment of this in- 10 de vention wherein it is desired to form a metal printing condensate ofan plate by using a low activity developer, it has been a"Pmnic found desirable to add a layer of ionic surfactants such as disclosed in US. Pat. No. 3,157,502 such as Armac EXAMPLES 1 13 121) (ionic Surfactant) and Synthrapol N (non-ionic 15 A stabilized physical developer was prepared by first surfactant) to the photographic element. The surfacki up h foll wing developer l i tants may also be added to the layer of physical devel- S opment activator or layer of photosensitive material or FJMLCWHOASOOWHZO 7&4 grams physical development nuclei. It has been found that the s)r i grams presence of the ionic surfactant in the photographic elf z ii 38:8 ement results in metallic images of improved printing H= to liter capability significantly improving both print quality f fig g f ggfigfi variable concentration and run length of the printing plate, especially when the acetate) v low activity unitary physical developers are utilized to Symhmpm N fig cmccnmmn Same as Armac form the metallic image of the plate. R20 m l liter In a preferred embodiment of this invention compris- Mi tabllizing Amine variable concentration mg a photographic stabilized physical developer com- Acetic Acid weight oncentration same as amine prising a solution of silver ions, ferrous ions, ferric ions, g N m gf Same as Armac 12D, Synthrapol N, and oleyl amine, it has been z g h H w found Posslble F Vary the pfopemes of e developer The stabilized physical developer was of the following by merely varying the relative concentrations of the composition; three surfactants, |.e., Armac 12D, Synthrapol N, and 250 m1 of Solution I oleyl amine. The Armac 12D tends to inhibit back- 50 ml of solution n ground fog in the final developed image and tends to 6 1 f 3 AgNQ3 increase the Photographic gamma of the final P Silver concentrations were determined by titration The oleyl amine, the other hand, tends to Produce with sodium thiocyanate solution. The accompanying a 10W gamma having a longer y Scale but tends to Table 1 shows the determined silver ion concentration Produce fog in the background- Also the oleyl amine as a function of time after mixing of the developer. The tends to Produce lustrous 5 Percent dots when P- initial concentration of a stable solution is 0.0588 Moing a halftone image of 5 percent dots for use as a prin lar. The developers were stored in airtight brown coling pl e- A as mentioned pr y, the oleyl ored bottles at ambient conditions (about 72F). amine adds great stability to the stabilized physical de- With t any i i f t t nt i th physical v l p The Sy po 011 the other hand, tends to developer formulation of Examples l-l3, the concen- SOlUbiliZe the ionic amines, thereby allowing a g r 45 tration of the silver ion within a matter of a few minutes amount of the surfactants to be present in the physical drops well below 0.045 grams/liter. developer for increasing the life of the developer. The The silver ion concentration in a completely stable formulas of these three surfactants are as follows: solution would, of course, remain constant at the initial TABLE 1 Time (hrs) before concentrations of silver ion dropped Example to:

No. Stabilizing Amine Surfactant Concentrations (gms/l) .055M .050M .045M

1 Armac 12D 90% dodecylamine acetate 1.25 45 I30 I 9% tetradecylamine acetate 2 do. do. 1.00 22 I30 170 3 do. do. 0.75 22 I10 165 4 do. do. 0.50 5 5 do. do. 0.25 2 5 l5 6 Alamine I5 90% C unsaturated primary amine (oleyl 1.25 280 510 730 amine and linoleyl amine) 9% C saturated primary amine 1% C, saturated primary amine 7 do. do. 1.00 300 720 1000 8 do. do. 0.75 500 H00 1400 9 Alamine l l (oleylamine) 1.25 800 I500 3000 10 Y 0. do. L0!) 900 3000 3000 ll do. do. 0.75 20 3000 3000 12 do. do. 0.50 23 70 l500 l3 4 14 do. do.

value. Thus the slower the concentration decreases the more stable the physieal developer is.

EXAMPLES 14 21 A stabilized physical developer is prepared by first formulating Solutions I and 11 as follows:

Solution 1 Fe(NH (SO ),-6H O 94.23 grams Fe(NO -9H O 38.82 grams citric aciclH o 96.12 grams 1120 to 1 liter 10 Solution 11 Stabilizing Amine variable concentration Acetic Acid 1 gram Synthropol N 1.2 grams H2O to 1 liter The stabilized physical developer is of the following composition:

Solution 1 220 ml. Solution 11 40 ml. 0.566M AgNO 70 ml. 2

0 The initial silver ion concentration before-any reaction occurs is theoretically 0.120M in stabilized physical developers of the above composition.

The stability was measured in the manner outlined in Examples l-l3. The results are compiled in Table 2.

EXAMPLE 22 Polyester film base coated with 1.5 g/m of a finely divided titanium dioxide in a binder of gelatin and polymethylmethacrylate was used in these two examples.

The stabilized physical developer formulation was as follows:

to form the developer. The mixed developer is stable several months with no change in silver concentration or activity.

The film was exposed to a step table 10' sec. on an EGG sensitometer, contacted for 5 sec. with an aqueous solution of 0.05M AgNO rinsed 5 sec. in H O, the above physical developer developed for 30 sec. at 78F, rinsed 5 sec. in H O, fixed 5 sec. in a standard silver halide fixing bath, rinsed 10 sec. in H 0, and dried 10 sec. in 140F air stream. An excellent neutral gray image of silver resulted.

EXAMPLE 23 The film of Example 22 was exposed and processed at 100 ft/min on an ltek Flowfilm printer/processor. A 200 watt mercury vapor lamp was used as the exposure device. The exposed film was then developed 1 min. in the stabilized physical developer of Example 22 at 78F,

rinsed 5 sec. in H O,

fixed 5 sec. in a standard silver halide fixing bath,

rinse 10 sec. in H 0, and

dried 10 sec. in 140F air stream. A neutral grey image having Dmax 1.8 and 1.58.

A batch of this stabilized physical developer to process the film of Example 22 has been used in the Flowfilm automatic processor for several months with replenishment only of silver ion and ferrous ion as required to maintain a relative constant consumption of (AB 88) 8 these ions in the developer. Solution 3 Duplicating this example except for omission of the gggfiggdggg 52-52 oleylamine from the developer leads to rapid deterio- Malic Acid 2 16.34 grams ration of the developer in the automatic processor Malomc Acld 195,0 grams within a few hours of continual use even with replenish- H,0 to I liter ment of silver ion and ferrous ion.

TABLE 2 Time (hrs) before concentrations of silver ion dropped Example to:

N0. Stabilizing Amine Surfactant Concentrations (gms/l) .10M .08M

14 Myristoleylaminc (lacks purity) .79 1 168 15 Palmitoleylamine (lacks purity) .90 200 336 115 oleylamine (lacks purity) 1.0 180 336 l7 Alamine 26D (oleyl amine and saturated amine .97 1 336 l8 Oley lamine 1.0 500 500 l9 Dodecylamine .75 40 20 Tetradecylamine .80 l 8 21 Hexadecylamine .90 l 1.5

Solution 11 EXAMPLE 24 Dodec lamine 0.1634 ram oleylaznine 0245] g A brush grained, anodized sheet of 1100 alloy alumia 8-2322 gram num was coated with a fine grained AgCl emulsion in ynt ropo gram AgNoa 16 gram polyvinyl alcohol. The 811111181011 had a mean particle H O to 1 liter size of 100A and contained the physical development Solutions 1 and 11 are mixed on an equal volume basis sensitizer tetramethyl thiuram disulfide in the amount of l mg/g AgCI. The plates were coated on a roller coater to a silver coverage of l X 10 g/m and a dry thickness of about .03 micron.

Plate thus coated were exposed through a negative 1% minutes to a 625 watt quartz-iodide source at 30 inches and then developed for 3 minutes in the following developer:

Solution Fe(NH,) (SO,),6H O 78.4 grams Fe(NO -9H,O 32.3 grams Citric Acid'H o 80.0 grams H O to 1 liter Solution ll Alamine 4 L6 grams Alamine ll 0.8 gram Acetic Acid 2.4 gram Syntropol N 0.75 gram H,O to 1 liter The stabilized physical developer is made by mixing:

125 ml Solution l 25 ml Solution ll 6 ml 3M AgNO,

Excellent metallic silver images reproducing the full range of halftone dots resulted. The image silver in solid image areas was in the amount of 10 g/m The plate was rinsed and treated with a lacquer such as is used to work up diazo plates, to which Z-mercaptobenzothiazole was added. The plate was then treated with a solution of gum arabic, as is conventionally done, and placed on a 26 inch Harris Aurelia press. 500,000 sharp, clear impressions were obtained. Excellent stability of the stabilized physical developer allowed it to be utilized continually for several hours in an automatic processor with a replenishment system which maintained a relatively stable concentration of silver ions and ferrous ions.

We claim:

1. In a stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of a water soluble silver salt reducible to silver, a photographic reducing agent for reducing said silver salt to silver comprising ferrous ions and ferric ions, at least one ionic surfactant as a stabilizing agent to increase the life of the developer, the improvement wherein at least one of said ionic surfactants comprises a water soluble salt of an alkenyl amine having at least eight carbon atoms present in the hydrocarbon chain of the alkenyl group.

2. A developer as in claim 1 wherein the water soluble silver salt comprises silver nitrate.

3. A developer as in claim 1 wherein the alkenyl amine is a primary amine.

4. A developer as in claim 1 wherein the salt of the alkenyl amine is present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer except without the salt of the alkenyl amine.

5. A developer as in claim 1 additionally comprising a primary alkyl amine as an additional ionic surfactant and wherein the alkyl group thereof contains at least eight carbon atoms.

6. A developer as in claim 5 additionally comprising a non-ionic surfactant.

7. A developer as in claim 1 wherein the AB is at least I millivolts.

8. A developer as in claim 1 wherein the AE of the developer is less than 100 millivolts.

9. A developer as in claim 5 wherein the AE of the developer is between about and 400 millivolts.

10. In a stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of silver ions, a photographic reducing agent for the silver ions comprising ferrous ions and ferric ions, an organic acid which complexes the ferric ions, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having an alkenyl group having at least eight carbon atoms in the hydrocarbon chain.

11. A developer as in claim 10 wherein the alkenyl amine is a primary amine.

12. A developer as in claim 10 wherein the salt of the alkenyl amine is present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer except lacking the alkenyl amine.

13. A developer as in claim 10 wherein a second ionic surfactant is present.

14. A developer as in claim 13 wherein the second ionic surfactant is the water soluble salt of a primary alkyl amine wherein the alkyl group has at least eight carbons present in the hydrocarbon chain.

15. A stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of silver ions, ferrous ions, ferric ions, an organic acid for complexing the ferric ions, an ionic surfactant comprising a water soluble salt of an alkenyl amine having at least eight carbon atoms in the hydrocarbon chain of the alkenyl group attached to the nitrogen atom, and a non-ionic surfactant as a solubilizing agent for the ionic surfactant in the developer.

16. A developer as in claim 15 wherein the complexing organic acid is citric acid, tartaric acid, malonic acid, malic acid or a combination of these acids.

17. A developer as in claim 15 wherein the pH of the physical developer is less than 3.

18. A developer as in claim 15 comprising an additional different ionic surfactant.

19. A stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of a water soluble silver salt reducible to silver metal, a ferrous compound, a ferric compound, an organic acid as a complexing agent for the ferric ions of the ferric compound, and a water soluble salt of oleyl amine as a stabilizing agent to lengthen the life of the developer.

20. A developer as in claim 19 additionally comprising a primary alkyl amine ionic surfactant comprising C H NH CH COOH and C H NH CH COOH.

21. A developer as in claim 20 additionally comprising a non-ionic surfactant.

22. In a photographic physical development process comprising contacting a copy medium comprising a catalytic nuclei image which is capable of selectively catalyzing physical development on said image, with a stabilized physical developer having an acidic pH and comprising an aqueous solution of silver ions, a photographic ferrous/ferric reducing agent for reducing these silver ions to silver metal, and at least one ionic surfactant as a stabilizing agent to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having at least eight carbon atoms in the hydrocarbon chain of the alkenyl group.

23. Process as in claim 22 wherein the pH of the physical developer is less than about 3.

24. Process as in claim 22 additionally comprising a different ionic surfactant.

25. Process as in claim 24 wherein said additional ionic surfactant is a water soluble salt of a primary alkyl amine compound wherein the alkyl group has at least eight carbon atoms present in the hydrocarbon chain.

29. In a photographic physical development process comprising exposing a copy medium comprising a photoconductor to produce a catalytic nuclei image in the medium and contacting the exposed medium with a stabilized photographic physical developer comprising a solution of silver ions, a photographic reducing agent for reducing the silver ion to silver metal comprising ferrous ions and ferric ions, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant comprises a water soluble salt of an alkenyl amine compound having at least eight carbon atoms present in the hydrocarbon chain of the alkenyl group, said alkenyl amine compound being present in an amount to increase the life of the developer at least 50 percent when compared to the life of an identical developer without the surfactant.

30. A process as in claim 29 additionally comprising a second different ionic surfactant.

31. Process as in claim 30 wherein said second different ionic surfactant is a water soluble salt of a primary alkyl amine compound wherein the alkyl group contains at least eight carbon atoms.

32. Process as in claim 30 additionally comprising a non-ionic surfactant.

33. In a process of producing a film transparency comprising contacting a copy medium comprising a transparent support comprising a catalytic nuclei image for catalyzing deposition of metal in these image areas from a physical developer with a stabilized photographic physical developer comprising a solution of silver ions, ferrous ions, ferric ions, complexing organic acid, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having an alkenyl group having at least eight carbons in the hydrocarbon chain.

34. Process as in claim 33 wherein the alkenyl amine is a primary amine.

35. Process as in claim 34 wherein the alkenyl amine is oleyl amine.

36. Process as in claim 35 additionally comprising a second ionic surfactant.

37. Process as in claim 36 wherein the different ionic surfactant is a water soluble salt of a primary alkyl amine compound.

38. Process as in claim 37 additionally comprising a non-ionic surfactant compound as a solublizing agent for the ionic surfactant in the physical developer.

39. Process as in claim 33 wherein the complexing organic acid comprises malic acid, malonic acid or a combination of these acids. 

2. A developer as in claim 1 wherein the water soluble silver salt comprises silver nitrate.
 3. A developer as in claim 1 wherein the alkenyl amine is a primary amine.
 4. A developer as in claim 1 wherein the salt of the alkenyl amine is present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer except without the salt of the alkenyl amine.
 5. A developer as in claim 1 additionally comprising a primary alkyl amine as an additional ionic surfactant and wherein the alkyl group thereof contains at least eight carbon atoms.
 6. A developer as in claim 5 additionally comprising a non-ionic surfactant.
 7. A developer as in claim 1 wherein the Delta E is at least 100 millivolts.
 8. A developer as in claim 1 wherein the Delta E of the developer is less than 100 millivolts.
 9. A developer as in claim 5 wherein the Delta E of the developer is between about 100 and 400 millivolts.
 10. In a stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of silver ions, a photographic reducing agent for the silver ions comprising ferrous ions and ferric ions, an organic acid which complexes the ferric ions, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having an alkenyl group having at least eight carbon atoms in the hydrocarbon chain.
 11. A developer as in claim 10 wherein the alkenyl amine is a primary amine.
 12. A developer as in claim 10 wherein the salt of the alkenyl amine is present in an amount sufficient to increase the life of the developer at least 50 percent when compared to the life of an identical developer except lacking the alkenyl amine.
 13. A developer as in claim 10 wherein a second ionic surfactant is present.
 14. A developer as in claim 13 wherein the second ionic surfactant is the water soluble salt of a primary alkyl amine wherein the alkyl group has at least eight carbons present in the hydrocarbon chain.
 15. A stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of silver ions, ferrous ions, ferric Ions, an organic acid for complexing the ferric ions, an ionic surfactant comprising a water soluble salt of an alkenyl amine having at least eight carbon atoms in the hydrocarbon chain of the alkenyl group attached to the nitrogen atom, and a non-ionic surfactant as a solubilizing agent for the ionic surfactant in the developer.
 16. A developer as in claim 15 wherein the complexing organic acid is citric acid, tartaric acid, malonic acid, malic acid or a combination of these acids.
 17. A developer as in claim 15 wherein the pH of the physical developer is less than
 3. 18. A developer as in claim 15 comprising an additional different ionic surfactant.
 19. A stabilized photographic physical developer having an acidic pH and comprising an aqueous solution of a water soluble silver salt reducible to silver metal, a ferrous compound, a ferric compound, an organic acid as a complexing agent for the ferric ions of the ferric compound, and a water soluble salt of oleyl amine as a stabilizing agent to lengthen the life of the developer.
 20. A developer as in claim 19 additionally comprising a primary alkyl amine ionic surfactant comprising C12H25NH2CH3COOH and C14H29NH2CH3COOH.
 21. A developer as in claim 20 additionally comprising a non-ionic surfactant.
 22. In a photographic physical development process comprising contacting a copy medium comprising a catalytic nuclei image which is capable of selectively catalyzing physical development on said image, with a stabilized physical developer having an acidic pH and comprising an aqueous solution of silver ions, a photographic ferrous/ferric reducing agent for reducing these silver ions to silver metal, and at least one ionic surfactant as a stabilizing agent to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having at least eight carbon atoms in the hydrocarbon chain of the alkenyl group.
 23. Process as in claim 22 wherein the pH of the physical developer is less than about
 3. 24. Process as in claim 22 additionally comprising a different ionic surfactant.
 25. Process as in claim 24 wherein said additional ionic surfactant is a water soluble salt of a primary alkyl amine compound wherein the alkyl group has at least eight carbon atoms present in the hydrocarbon chain.
 26. Process as in claim 25 wherein the developer additionally comprises a non-ionic surfactant.
 27. Process as in claim 22 wherein the Delta E of the developer is greater than
 100. 28. Process as in claim 22 wherein the Delta E is less than
 100. 29. In a photographic physical development process comprising exposing a copy medium comprising a photoconductor to produce a catalytic nuclei image in the medium and contacting the exposed medium with a stabilized photographic physical developer comprising a solution of silver ions, a photographic reducing agent for reducing the silver ion to silver metal comprising ferrous ions and ferric ions, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant comprises a water soluble salt of an alkenyl amine compound having at least eight carbon atoms present in the hydrocarbon chain of the alkenyl group, said alkenyl amine compound being present in an amount to increase the life of the developer at least 50 percent when compared to the life of an identical developer without the surfactant.
 30. A process as in claim 29 additionally comprising a second different ionic surfactant.
 31. Process as in claim 30 wherein said second different ionic surfactant is a water soluble salt of a primary alkyl amine compound wherein the alkyl group contains at least eight carbon atoms.
 32. Process as in claim 30 additionally comprising a non-ionic surfactant.
 33. In a process of producing a film transparency comprising contacting a copy medium comprising A transparent support comprising a catalytic nuclei image for catalyzing deposition of metal in these image areas from a physical developer with a stabilized photographic physical developer comprising a solution of silver ions, ferrous ions, ferric ions, complexing organic acid, and at least one ionic surfactant to increase the life of the developer, the improvement wherein at least one ionic surfactant is a water soluble salt of an alkenyl amine compound having an alkenyl group having at least eight carbons in the hydrocarbon chain.
 34. Process as in claim 33 wherein the alkenyl amine is a primary amine.
 35. Process as in claim 34 wherein the alkenyl amine is oleyl amine.
 36. Process as in claim 35 additionally comprising a second ionic surfactant.
 37. Process as in claim 36 wherein the different ionic surfactant is a water soluble salt of a primary alkyl amine compound.
 38. Process as in claim 37 additionally comprising a non-ionic surfactant compound as a solublizing agent for the ionic surfactant in the physical developer.
 39. Process as in claim 33 wherein the complexing organic acid comprises malic acid, malonic acid or a combination of these acids. 